The present invention relates to dry cleaning facilities and specifically relates to a system for recirculating a coolant employed in conjunction with the dry cleaning fluids.
The dry cleaning industry has long utilized various approaches to recondition or rehabilitate the various solvents employed as the dry cleaning fluids, and the use of apparatus such as condensing stills and the like is well known. Typical of dry cleaning fluids are the well known carbon tetrachloride and perchloroethylene. Nevertheless, whatever the dry cleaning fluid employed, it will be a petroleum distillate. Needless to say the costs of such petroleum distillates have risen to the point where recovery and reconditioning of same has become economically important. Additionally, federal and state regulations, such as those promulgated by OSHA, have required various types of vapor collection and the like in order to reduce health hazards to the dry cleaning plant personnel.
When reclaiming or reconditioning dry cleaning solutions or fluids, it is known to utilize a reclaimer condensor to condense the vapors and also to use a still or the like to separate the impurities from the dry cleaning solution. Both of these units require a supply of coolant for efficient operation, and conventional practice is to utilize a continuous flow of water from the municipal water supply as such coolant. Additionally, perchloroethylene dry cleaning fluid must be used at a relatively low temperature in order to maintain its efficiency. As is known, the cleaning fluid is best maintained below 90.degree. F. because the detergent added to the cleaning fluid loses its ability to hold "free" water. Even a few ounces of free water in as much as 100 gallons of perchloroethylene will cause wrinkling and color loss in some fabrics (e.g., silk and cotton) just as if they had been placed in a conventional washing machine. This cooling operation is done with a coolant coil which typically also receives its low temperature coolant from the municipal water supply main. Also, what is commonly known as a "sniffer" may optionally be employed where required by occupational regulations, and this serves to capture the dry cleaning fluid vapors from the air and to prevent adverse contact with the operating personnel. The sniffer condenses perchloroethylene from the air that is passed through a charcoal filter. From time to time, two to five days a week, for an hour at a time, live steam is driven through the charcoal filter, thereby vaporizing the perchloroethylene in the charcoal. The steam and perchloroethylene vapors are then passed through the sniffer cooling coils and the condensed perchloroethylene and water are separated. This perchloroethylene is then ready for reuse.
Again, all of these condensers, stills, sniffers and the like employ coolant coils through which the readily available cold water from the municipal water supply is continuously permitted to flow. Of course, some dry cleaning facilities may have their own well but, nevertheless, the water used for cooling is the same water that is available for use throughout the dry cleaning facility.
Now, in the past it has been the practice simply to connect the exit sides of the cooling coil to the drain and to permit the water to flow continuously through the coils. This system works well and without problems, however, in many areas of the country not only is there a water supply problem, but also water rates have risen to the point where the economics of the coolant water supply have increased the cost of providing dry cleaning services. Moreover, some municipalities are restricting the quantities of water permitted for various industrial and home uses.